When a particle is projected at some angles to the horizontal,it has a range R and time of flight t1. If the same particle is projected with same speed at some other angle to have the same range its time of flight is t2, then,1. t1 + t2 = 2R/g2. t1 - t2 = R/g3. t1t2 = 2R/g4. t1t2 = R/g